Brian David Josephson

(1940 - )

Brian David Josephson was born in Cardiff, Wales, UK
on January 4, 1940. Josephson attended Trinity College, Cambridge and
obtained his his bachelor’s (1960) and masters and Ph.D. (1964)
from Trinity. In 1962, Josephson was elected a fellow of Trinity College.

From 1965 to 1966, Josephson became a research professor
at the University of Illinois. In 1967, he returned to Cambridge as
assistant director of research. He is currently a professor at the University
of Cambridge where he is the head of the mind-matter unification project
in the Theory of Condensed Matter research group.

As an undergraduate student, he became fascinated
in superconductivity, where he advanced research of tunneling. Tunneling
is when electrons penetrate solids, as radiated waves. He illustrated
that when a voltage is applied during tunneling between superconductors,
the current stops and oscillates at a higher frequency. This was named
the Josephson effect. This discovery won him the 1973 Nobel
Prize for Physics, which he shared with Leo Esaki and Ivar Giaever.

Josephson is one of the most well-known advocates
of the possibility of the existence of paranormal phenomena. He has
said that the scientist's motto should be, "Take nobody's word
for it" (nullius in verba), which he says also includes the idea
that, "if scientists as a whole denounce an idea this should not
necessarily be taken as proof that the said idea is absurd: rather,
one should examine carefully the alleged grounds for such opinions and
judge how well these stand up to detailed scrutiny."

The following press release from the Royal Swedish Academy of Sciences
describes Josephson’s work:

The Laws of Modern Physics

Tunneling phenomena are among the most direct consequences
of the laws of modern physics. According to quantum physics electrons
behave both like particles and like waves and are described by the
solutions to the so-called Schroedinger equation. These waves can
penetrate a barrier that would be a forbidden area if the particle
was considered in the classical way. The term tunneling phenomenon
refers to this property - the particle "tunnels" through
the forbidden area. The best-known case of tunneling is the alpha
decay of heavy atomic nuclei, which was explained as early as 1928.

The possible existence of many interesting tunneling
phenomena in solids was anticipated at an early stage, but theory
and experiments often gave contradictory results. The discovery of
the transistor and the consequent development of semiconductor physics
intensified the search for new tunnel effects, but it was unsuccessful
for many years.

Pioneering Work

Thanks to the pioneering work of Esaki, Giaever
and Josephson, this year's physics laureates, the study of tunneling
phenomena in solids has developed into a large and very active field
of research that has led to many important results of a fundamental
character and has opened new doors for technical applications. The
initial work was done by Leo Esaki, who at that time was working in
the Sony Corporation research laboratory in Japan. By means of some
deceptively simple experiments he proved in a paper published in 1958
the existence of a new kind of tunneling phenomenon in a semiconductor.
His discovery also showed that this effect could be used technically
in so-called tunnel diodes. Esaki's discovery opened up a new field
of research and initiated intensive and successful developments at
many international research laboratories.

The next important step was taken in 1960 by Ivar
Giaever at General Electrics research laboratory at Schenectady. He
demonstrated the tunnel effect through a very thin layer of oxide
surrounded on both sides by metal in a superconducting or normal state.
His experiment gave very direct evidence of the existence of the so-called
energy gap in superconductors, which was one of the most important
predictions of the theory of superconductivity developed by Bardeen,
Cooper and Schrieffer (awarded the Nobel Prize in 1972). In his later
work Giaever developed his tunnel experiments into an extremely accurate
spectroscopic method for studying superconductors.

Theoretical Description- The Josephson Effects

Giaever's tunnel experiments inspired the young
English physicist Brian D Jospehson to analyse more closely the theoretical
description. In 1962 this led to the prediction of completely new
phenomena in superconductors and in particular to the effects generally
known as the Josephson effects. One of these effects means that a
supercurrent can flow through a tunnel barrier even when no voltage
is applied to the barrier. The second effect is even more peculiar,
showing that a constant difference of voltage across the barrier results
in a high-frequency tunnel current in the microwave range. Josephson's
theoretical predictions were confirmed by experiments within a year
or so and have had a strong influence on developments in physics in
recent years.

Independent Work

The discoveries of these three physicists were made
quite independently but are closely related. Esaki's pioneering work
in 1958 provided the basis for Giaever's tunnel experiments with superconductors
in 1960. In turn, Giaever's work created the basis and stimulus for
Josephson's theoretical discoveries in 1962. Their discoveries have
opened up new areas for research and have recently led to a number
of important applications, to which a large number of physicists have
contributed. Examples of applications in the field of semiconductors
are tunnel diodes and tunnel detectors, tunnel transistors and certain
forms of semiconductor lasers. The Jospehson effects have resulted
in a revision of the values of the fundamental constants, a new method
for accurately measuring voltages and an extremely sensitive interferometric
method which has many applications in the technology of precision
measurement.”